TWI832812B - Liquid-crystalline medium and liquid-crystal display comprising the same - Google Patents

Abstract

The present invention relates to a liquid-crystalline medium (LC medium) comprising a polymerizable piperidine derivative as an additive for stabilization, to the use thereof for electro-optical purposes, and to LC displays containing this medium, particularly to liquid-crystal displays which use the IPS (in-plane switching) or the FFS (fringe field switching) effect using dielectrically positive liquid crystals.

Description

Liquid crystal media and liquid crystal displays containing them

The present invention relates to a liquid crystal medium (LC medium) containing a polymerizable piperidine derivative as an additive for stabilization, to its use for electro-optical purposes, and to LC displays containing this medium, in particular to Use a liquid crystal display that utilizes the in - plane switching (IPS ) or fringe field switching (FFS) effect of dielectric positive liquid crystals.

Liquid crystals are primarily used as dielectrics in display devices because the optical properties of these substances can be modified by the application of voltage. Those skilled in the art are very familiar with liquid crystal based electro-optical devices and can be based on various effects. Examples of such devices are cells with dynamic scattering, deformation of aligned phase (DAP) cells, guest/host cells, TN cells with a "twisted nematic" structure, "supertwisted nematic"("supertwistednematic")"super-twistednematic" (STN) unit, "superbirefringence effect" (SBE) unit and "optical mode interference" (OMI) unit. The most common display device is based on the Schadt-Helfrich effect and has a twisted nematic structure. In addition, there are also cells that operate by an electric field parallel to the substrate and the liquid crystal plane, such as "in-plane switching" (IPS) cells. TN, STN, fringe field switching (FFS) and IPS units are particularly currently commercially interesting application areas for media according to the present invention. Liquid crystal materials must have good chemical and thermal stability as well as good stability to electric fields and electromagnetic radiation. In addition, the liquid crystal material should have low viscosity and produce short address times, low threshold voltages and high contrast ratios in the cell. Furthermore, it should have suitable mesophases, such as nematic or cholesteric mesophases for the units mentioned above, at common operating temperatures, that is to say in the widest possible range above and below room temperature. Mutually. Since liquid crystals are usually used as a mixture of several components, it is important that the components are easily miscible with each other. Other properties such as electrical conductivity, dielectric anisotropy and optical anisotropy must meet various requirements depending on the unit type and application area. For example, materials used for cells with twisted nematic structures should have positive dielectric anisotropy and low conductivity. For example, for matrix LCDs with integrated nonlinear elements for switching individual pixels (MLC displays), large positive dielectric anisotropy, broad nematic phase, relatively low birefringence, extremely high Medium with specific resistance, good UV and temperature stability and low vapor pressure. Matrix liquid crystal displays of this type are known. Examples of non-linear elements that can be used to switch individual pixels individually are active elements (ie transistors). The term "active matrix" is then used, where a distinction can be made between two types: 1. Metal oxide semiconductor (MOS) or other diodes on a silicon wafer as substrate. 2. A thin-film transistor (TFT) on a glass plate is used as the substrate. The use of monocrystalline silicon as the substrate material limits the display size because even various partial display module assemblies can cause problems at the joints. In the case of the more promising type 2, which is better, the electro-optical effect used is usually the TN effect. A distinction is made between two technologies: TFTs containing compound semiconductors such as CdSe, or TFTs based on polycrystalline or amorphous silicon. The latter technology is being researched intensively around the world. The TFT matrix is applied to the interior of one glass plate of the display, while the other glass plate carries transparent counter electrodes on its interior. Compared with the size of pixel electrodes, TFTs are extremely small and have almost no adverse effects on images. This technology can also be extended to a fully colour-capable display, in which a mosaic of red, green and blue filters is arranged with filter elements facing each switchable pixel. TFT displays are commonly used as TN cells with crossed polarizers in transmission and are backlit. The term MLC display herein covers any matrix display with integrated nonlinear elements, that is, in addition to the active matrix, the display also has passive elements such as varistors or diodes (MIM = Metal-Insulator-Metal). This type of MLC display is particularly suitable for TV applications (such as pocket television) or high information displays for computer applications (laptops) and in automobile or aircraft construction. In addition to problems related to the angle dependence of contrast and response time, difficulties arise in MLC displays because the specific resistance of the liquid crystal mixture is not high enough [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E. , SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, September 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, pp. 141 et seq., Paris; STROMER, M., Proc. Eurodisplay 84, September 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, pp. 145 et seq., Paris]. As the resistance decreases, the contrast of the MLC display decreases, and the problem of afterimage elimination occurs. Because the specific resistance of the liquid crystal mixture typically decreases with the life of an MLC display due to interaction with the inner surface of the display, a high (initial) resistance is extremely important in order to obtain an acceptable lifetime. Particularly in the case of low-voltage mixtures, extremely high specific resistance values have not been possible so far. Additionally, it is critical that the specific resistance exhibits the smallest possible increase as the temperature increases and after heating and/or UV exposure. The low temperature properties of prior art mixtures are also particularly disadvantageous. It is necessary that no crystallization and/or smectic phases occur even at low temperatures and that the temperature dependence of the viscosity is as low as possible. Therefore, prior art MLC displays do not meet today's requirements. In addition to LCDs using backlights, ie operating in a transmissive manner and optionally in a transflective manner, reflective LCDs are also of particular interest. These reflective LCD displays use ambient light for information display. Therefore, it consumes significantly less energy than a backlit LCD display of comparable size and resolution. Because the TN effect is characterized by excellent contrast, such reflective displays can be read well even in bright ambient conditions. This is known as simple reflective TN displays such as those used in watches and pocket calculators. However, this principle can also be applied to high quality, higher resolution active matrix addressed displays such as TFT displays. Here, as in commonly known transmissive TFT-TN displays, it is necessary to use liquid crystals with low birefringence (Δn) in order to achieve low light blocking (d·Dn). This low light blocking results in a generally acceptable lower viewing angle dependence of the contrast (see DE 30 22 818). In reflective displays, the use of liquid crystals with low birefringence is even more important than in transmissive displays, because in reflective displays the effective layer thickness through which light passes is approximately the same as in transmissive displays with the same layer thickness twice. For TV and video applications, displays with fast response times are required to enable reproduction of multimedia content, such as movies and video games, with near-lifelike quality. These short response times can be achieved especially if a liquid crystal medium with a low viscosity value, especially a low rotational viscosity _γ1 value, and a high optical anisotropy (Δn) is used. In order to achieve the 3D effect with the aid of shutter glasses, fast-switching mixtures with low rotational viscosity and correspondingly high optical anisotropy (Δn) are used. With the help of an electro-optical lens system, the 2D image of the display can be converted into a 3D autostereoscopic image, which can be achieved using a mixture with high optical anisotropy (Δn). In the case of TN (Schaud-Helfrich) cells, media are needed that facilitate the following advantages in the cell: - Extended nematic phase range (especially down to low temperatures) - Switching capabilities at extremely low temperatures ( Outdoor use, automotive, avionics) - Improved UV radiation tolerance (longer service life) - Low threshold voltage. Media derived from prior art are unable to achieve these advantages while retaining other parameters. In the case of supertwisted (STN) cells, there is a need for media that facilitate greater multiplexing and/or lower threshold voltages and/or wider nematic phase range, especially at low temperatures. For this purpose, there is an urgent need to further broaden the available parameter latitude (clearing point, smectic-nematic transition or melting point, viscosity, dielectric parameters, elastic parameters). One of the most important characteristics of modern LCDs is the correct reproduction of moving images. If the response speed of the liquid crystal medium used is too slow, this can cause undesirable artifacts in displays of such content. Basically the physical parameters that determine the response time of a liquid crystal mixture are the rotational viscosity γ ₁ and the elastic constant. The latter is also particularly important to ensure good black status of the LCD. However, in general, it is observed that the clearing point of the mixture and therefore the rotational viscosity of the mixture also increases with increasing elastic constant, meaning that the response time is unlikely to be improved. Especially in the case of LC displays used in TV and video applications (such as LCD TVs, monitors, PDAs, notebook computers, game consoles), the response time required is significantly reduced. Reducing the layer thickness d ("cell gap") of the LC medium in an LC cell theoretically produces faster response times, but requires the LC medium to have a higher birefringence Δn to ensure adequate light blocking (d ^. Δn) . However, high birefringence LC materials known from the prior art usually also have high rotational viscosity, which in turn has a negative impact on the response time. Therefore, there is still a great need for liquid crystal media with good reliability properties, such as high voltage holding ratio (VHR), which do not exhibit these properties or only exhibit these properties to a small extent. The present invention is based on the object of providing media, in particular for IPS, FFS, HB (=High Brightness)-FFS, PS (=Polymer Stabilized)-FFS, PS-IPS displays of this type, which have the properties indicated above. required properties and exhibiting none of the disadvantages indicated above or only exhibiting the disadvantages indicated above to a reduced extent. In particular, the LC medium should have a fast response time and low rotational viscosity while having a relatively high birefringence. In addition, the LC medium should have a high clarity point and excellent low-temperature stability (LTS). However, according to the present application, the IPS or FFS effect is better with uniformly aligned dielectric positive liquid crystal media. Liquid crystal media with positive dielectric anisotropy have been disclosed for IPS and FFS displays. Some examples are given below. WO 2012/079676 A1 discloses a liquid crystal medium with high positive dielectric anisotropy. Publication WO 2013/182271 A1 discloses liquid crystalline media with positive dielectric anisotropy, which are additionally stabilized by Tinuvin 770®. In WO 2016/116119 A1 polymerizable piperidine derivatives as disclosed herein have been proposed as additives in polymerizable liquid crystal media. The industrial application of this effect in electro-optical display components requires an LC phase, which must meet various requirements. Of particular importance here is the chemical resistance against moisture, air and physical influences such as heat, radiation in the infrared, visible and ultraviolet regions, as well as direct current (DC) and alternating current (AC) electric fields. The term MLC display herein covers any matrix display with integrated nonlinear elements, that is, in addition to the active matrix, the display also has passive elements such as varistors or diodes (MIM = Metal-Insulator-Metal). Such MLC displays are particularly suitable for TV applications, monitors and notebook computers or for displays with high information density, such as those used in automobile manufacturing or aircraft construction. In addition to problems related to the angle dependence of contrast and response time, difficulties arise in MLC displays because the specific resistance of the liquid crystal mixture is not high enough [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E. , SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, September 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, pp. 141 et seq., Paris; STROMER, M., Proc. Eurodisplay 84, September 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, pp. 145 et seq., Paris]. As the resistance decreases, the contrast ratio of the MLC display deteriorates. Since the specific resistance of the liquid crystal mixture typically decreases with the life of the MLC display due to interaction with the inner surface of the display, high (initial) resistance is extremely important for displays that must have acceptable resistance values over long periods of operation. This type of media is particularly useful in electro-optical displays with active matrix addressing for IPS or FFS displays. It has now been found that this objective can be achieved if an LC medium containing one or more compounds of formula I is used.

Surprisingly, it has been found that it is possible to obtain liquid crystal displays, especially in IPS and FFS displays, with a low threshold voltage with a short response time, a sufficiently wide nematic phase, a favorable birefringence (Δn) and at the same time a high transmittance, by Good stability to decomposition by heating and by UV exposure, and stable high VHR in the case of using nematic liquid crystal mixtures containing at least one compound of the formula I or a polymer containing a polymerized form thereof, P-Sp- (A ² -Z ² -A ¹ ) _m1 -Z ¹ -TI in which the groups independently of each other and on each occurrence the same or different have the following meanings T is selected from the group consisting of the following formulas R ^g H or linear or branched alkyl or alkoxyalkyl having 1 to 10 C atoms, preferably 1 to 6 C atoms, most preferably 1 to 4 C atoms, or benzyl , preferably H, R ^a , R ^b , R ^c , R ^d have 1 to 10 C atoms, preferably 1 to 6 C atoms, preferably straight or branched chains with 1 to 4 C atoms Alkyl group, P vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane or epoxy group, preferably acrylate, methacrylate, fluoroacrylate, Chloroacrylate, and more preferably acrylate or methacrylate, most preferably methacrylate, Sp spacer group or single bond, A ¹ and A ² have an alicyclic group of 4 to 30 ring atoms, hetero Cyclic, aromatic or heteroaromatic groups, which may also contain fused rings and are optionally substituted by one or more groups L or R-(A ³ -Z ³ ) _m2 -, and in A ¹ and A ² One of them can also represent a single bond. A ³ has an alicyclic group, a heterocyclic group, an aromatic group or a heteroaromatic group with 4 to 30 ring atoms. It can also contain a fused ring and is optionally passed through one or more Group L substituted, Z ¹ -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -OCH ₂ -, -CH ₂ O-, -SCH ₂ -, -CH ₂ S-, -CF ₂ O-, -OCF 2 -, -CF _{2 S-} , -SCF ₂ -, -(CH ₂ ) _n -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -(CF ₂ ) _n -, -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -CºC-, -CH=CH-CO-O- , -O-CO-CH=CH-, -CH ₂ -CH ₂ -CO-O-, -O-CO-CH ₂ -CH ₂ -, -CR ⁰⁰ R ⁰⁰⁰ - or single bond, the restriction condition is if m1 is 0, then Z ¹ is a single bond, Z ² , Z ³ -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -OCH ₂ -, -CH ₂ O-, -SCH ₂ -, -CH ₂ S-, -CF ₂ O-, -OCF ₂ -, -CF ₂ S-, -SCF ₂ -, -(CH ₂ ) _n -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -(CF ₂ ) _n -, -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -CºC-, -CH=CH-CO-O-, -O-CO-CH=CH-, -CH ₂ -CH ₂ -CO-O-, -O-CO-CH ₂ -CH ₂ -, -CR ⁰⁰ R ⁰⁰⁰ - Or single bond, R ⁰⁰ , R ⁰⁰⁰ H or alkyl group with 1 to 12 C atoms, R P-Sp-, H, F, Cl, CN, or straight or branched chain with 1 to 25 C atoms or cyclic alkyl, in which one or more non-adjacent CH ₂ - groups are optionally represented by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO -O- substitution, in such a way that the O atoms and/or S atoms are not directly connected to each other, and one or more of the H atoms are replaced by F, Cl or P-Sp- respectively, as appropriate, or the group T, L P -Sp-, F, Cl, CN or straight chain, branched chain or cyclic alkyl group with 1 to 25 C atoms, one or more non-adjacent CH ₂ - groups are optionally represented by -O-, -S -, -CO-, -CO-O-, -O-CO-, -O-CO-O- are substituted in such a way that the O atoms and/or S atoms are not directly connected to each other, and one or more of the H atoms Each is optionally substituted by F, Cl or P-Sp-, or is selected from a group of formulas 1, 2 and 3, m1 0, 1, 2, 3 or 4, m2 0, 1, 2, 3 or 4, and n 1, 2, 3 or 4. The present invention relates to a liquid crystal medium having a nematic phase and a dielectric anisotropy (Δε) of 1.5 or greater, characterized in that it contains one or more compounds of the formula I as described above and below or contains one or Polymers of compounds of formula I in various polymeric forms.

The present invention relates more particularly to a liquid crystal medium comprising - a polymerizable component A) which comprises one or more polymerizable compounds, at least one of which is a compound of formula I, and - Liquid crystal component B), hereinafter also referred to as "LC host mixture", contains, preferably consists of, one or more mesogens or liquid crystal compounds. The liquid crystal component B) of the liquid crystal medium according to the invention is also referred to as "LC host mixture" in the following and preferably contains one or more, preferably at least two, mesogens or LC selected from non-polymerizable low molecular weight compounds. compound. Furthermore, the invention relates to a liquid-crystalline medium as described above and below, wherein the LC host mixture or component B) contains at least one mesogen or LC compound containing alkenyl groups. Furthermore, the invention relates to a liquid crystal medium or LC display as described above and below, in which the compound of formula I or the polymerizable compound of component A) is polymerized. Furthermore, the present invention relates to a method for preparing a liquid crystal medium as described above and below, which method comprises the step of combining one or more mesogens or LC compounds or an LC host mixture or LC group as described above and below. Part B) is mixed with one or more compounds of formula I and, optionally, other LC compounds and/or additives. This type of media is particularly useful in electro-optical displays with active matrix addressing for IPS or FFS displays. The medium according to the invention preferably additionally contains one or more compounds selected from the group of compounds of formula II and compounds of formula III, preferably one or more compounds of formula II, more preferably another one or more compounds of formula III, and most preferably another or a plurality of compounds selected from the group of compounds of formula IV and compounds of formula V. The mixture according to the present invention exhibits an extremely wide nematic phase range at a clearing point ≥70°C, has a relatively high retention rate (VHR) value, an extremely favorable capacitance threshold value, and simultaneously operates at -20°C and -30°C. Excellent low temperature stability at ℃ and extremely low rotational viscosity. Furthermore, the mixtures according to the invention are distinguished by a good ratio of clearing point and rotational viscosity and a relatively high positive dielectric anisotropy. Notably, the reliability of the mixture was improved. Very little image burning was observed. High voltage retention even after extended use or similarly after standard aging tests such as accelerated light load, thermal or UV testing. On the one hand, preferably, the dielectric anisotropy value of the liquid crystal medium according to the present invention is 2 or more, preferably 3.5 or more preferably 4.5 or more. On the other hand, its dielectric anisotropy is preferably 25 or less. In a preferred embodiment, the positive dielectric anisotropy of the liquid crystal medium according to the present invention is preferably in the range of 2.0 or more to 25 or less, more preferably in the range of 3.0 or more to 22 or less range, and optimally within the range of 8.0 or greater to 20 or less. All % are by weight. The compound of formula I is preferably used at a concentration in the range of 0.0005 to 2% by weight, more preferably in the range of 0.001 to 1% by weight, especially preferably in the range of 0.005 to 0.05% by weight. Liquid crystal media. The total content of polymerizable or polymerizable components in the liquid crystal medium according to the present invention is preferably less than 0.1% by weight, more preferably less than 0.05% by weight, and most preferably less than 0.02% by weight (200 ppm). The liquid crystal medium preferably contains a) one or more compounds of formula I, b) one or more dielectric compounds selected from the group of compounds of formula II and compounds of formula III, preferably selected from the group of compounds with dielectric anisotropy each greater than 3. Positive compounds: Where R ² represents an alkyl group, alkoxy group, fluorinated alkyl group or fluorinated alkoxy group with 1 to 7 C atoms, an alkenyl group, alkenyloxy group, alkoxyalkyl group with 2 to 7 C atoms. group or fluorinated alkenyl group, and preferably represents an alkyl group or alkenyl group, ^{L 21} and L ²² represent H or F, preferably L ²¹ represents F, and Or alkenyloxy group, preferably F, Cl, -OCF ₃ , -O-CH ₂ CF ₃ , -O-CH=CH ₂ , -O-CH=CF ₂ or -CF ₃ , most preferably F, Cl, CF ₃ , -O-CH=CF ₂ or -OCF ₃ , m represents 0, 1, 2 or 3, preferably 1 or 2 and particularly preferably 1, R ³ represents 1 to 7 C atoms alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, and preferably alkyl or alkenyl, L ³¹ and L ³² independently represent H or F, preferably L ³¹ represents F, and X ³ represents halogen, halogenated alkyl or alkoxy group with 1 to 3 C atoms or 2 or 3 C atoms. Halogenated alkenyl or alkenyloxy, F, Cl, -OCF ₃ , -OCHF ₂ , -O-CH ₂ CF ₃ , -O-CH=CF ₂ , -O-CH=CH ₂ or -CF ₃ , Excellent means F, Cl, -O-CH=CF ₂ , -OCHF ₂ or -OCF ₃ , Z ³ means -CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -COO-, anti-CH=CH- , anti-CF=CF-, -CH ₂ O- or single bond, preferably means -CH ₂ CH ₂ -, -COO-, anti-CH=CH- or single bond, and best means -COO-, anti -CH=CH- or a single bond, and n represents 0, 1, 2 or 3, preferably 1, 2 or 3 and especially preferably 1, and c) optionally one or more of the formulas IV and V Group of dielectrically neutral compounds: wherein R ⁴¹ and R ⁴² independently have the meanings indicated above for R ² according to formula II, preferably R ⁴¹ represents an alkyl group and R ⁴² represents an alkyl group or an alkoxy group, or R ⁴¹ represents an alkenyl group and R ⁴² represents an alkyl group, Z ⁴¹ and Z ⁴² , independently of each other and if Z ⁴¹ appears twice, these groups also independently represent -CH ₂ CH ₂ -, -COO-, anti-CH=CH-, anti-CF=CF -, -CH ₂ O-, -CF ₂ O-, -C≡C- or single bond, preferably one or more of them represent a single bond, and p represents 0, 1 or 2, preferably 0 or 1 , and R ⁵¹ and R ⁵² , independently of each other, have one of the meanings given for R ⁴¹ and R ⁴² , and preferably represent an alkyl group having 1 to 7 C atoms, preferably represent an n-alkyl group, especially more Preferably represents an n-alkyl group having 1 to 5 C atoms, preferably represents an alkoxy group having 1 to 7 C atoms, preferably represents an n-alkoxy group, and particularly preferably represents an n-alkoxy group having 2 to 5 C atoms. radical, which means an alkoxyalkyl, alkenyl or alkenyloxy group having 2 to 7 C atoms, preferably having 2 to 4 C atoms, preferably alkenyloxy group, Preferably Preferably, And if exists, then Z ⁵¹ to Z ⁵³ each independently represent -CH ₂ -CH ₂ -, -CH ₂ -O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH ₂ -CH ₂ -, -CH ₂ -O- or a single bond, and particularly preferably represents a single bond, i and j each independently represent 0 or 1, (i + j) preferably represents 0, 1 or 2, more preferably Best means 0 or 1 and Best means 1. The liquid crystal medium according to the present application preferably has a nematic phase. The definition of alkyl throughout this application and in particular for R ¹ means alkyl, which may be straight or branched. Each of these groups is preferably straight chain, and preferably has 1, 2, 3, 4, 5, 6, 7 or 8 C atoms, and is accordingly preferably methyl, ethyl, n- Propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl. In the case where alkyl means branched chain alkyl, it preferably means 2-alkyl, 2-methylalkyl or 2-(2-ethyl)-alkyl, preferably 2-butyl ( =1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, especially 2-methylbutyl base, 2-methylbutoxy 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl and 2-dodecyl. Preferably these groups are 2-hexyl and 2-octyl. The respective branched chain groups, in particular for R ¹ which give rise to chiral compounds, are also referred to in this application as chiral groups. Particularly preferred chiral groups are 2-alkyl, 2-alkoxy, 2-methylalkyl, 2-methylalkoxy, 2-fluoroalkyl, 2-fluoroalkoxy, 2- (2-ethynyl)-alkyl, 2-(2-ethynyl)-alkoxy, 1,1,1-trifluoro-2-alkyl and 1,1,1-trifluoro-2-alkoxy. For example, particularly preferred chiral groups are 2-butyl (=1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2- Ethylhexyl, 2-propylpentyl, especially 2-methylbutyl, 2-methylbutoxy, 2-methylpentyloxy, 3-methylpentyloxy, 2-ethylhexyloxy base, 1-methylhexyloxy, 2-octyloxy, 2-oxa-3-methylbutyl, 3-oxa-4-methylpentyl, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methoxyoctyloxy, 6-methyloctyloxy, 6-methyloctyloxy, 5- Methylheptyloxycarbonyl, 2-methylbutyloxy, 3-methylpentyloxy, 4-methylhexyloxy, 2-chloropropyloxy, 2-chloro-3-methyl Butyloxy, 2-chloro-4-methylpentyloxy, 2-chloro-3-methylpentyloxy, 2-methyl-3-oxopentyl, 2-methyl-3- Oxahexyl, 1-methoxypropyl-2-oxy, 1-ethoxypropyl-2-oxy, 1-propoxypropyl-2-oxy, 1-butoxypropyl -2-oxy, 2-fluorooctyloxy, 2-fluorodecanyloxy, 1,1,1-trifluoro-2-octyloxy, 1,1,1-trifluoro-2-octyl, 2-Fluoromethyloctyloxy. Excellent ones are 2-hexyl, 2-octyl, 2-octyloxy, 1,1,1-trifluoro-2-hexyl, 1,1,1-trifluoro-2-octyl and 1,1,1 -Trifluoro-2-octyloxy. Compounds of formula I are prepared according to WO 2016/116119 A1 or are commercially available. Furthermore, the present invention relates to the use of liquid crystal mixtures and liquid crystal media according to the invention in IPS and FFS displays, especially in media containing liquid crystal, for improving the voltage-holding-ratio. Furthermore, the present invention relates to a liquid crystal display containing a liquid crystal medium according to the present invention, especially an IPS or FFS display, particularly preferably an IPS display. The display according to the present invention is preferably addressed by an active matrix LCD ( AMD for short), preferably by a thin film transistor (TFT) matrix. However, the liquid crystals according to the invention can also be used in an advantageous manner in displays with other known addressing methods. Furthermore, the invention relates to a method for preparing a liquid crystal medium according to the invention by mixing one or more compounds of the formula I with one or more low molecular weight liquid crystal compounds, or liquid crystal mixtures, and optionally with other liquid crystal compounds and/ Or additives are mixed to obtain a liquid crystal medium with a nematic phase and a dielectric anisotropy (Δε) of 1.5 or greater. The following meanings apply above and below: As used herein, the terms "reactive mesogen" and "RM" shall be understood to mean a reactive mesogen containing a mesogen or a liquid crystal skeleton attached thereto and suitable for polymerization reactions. Compounds with one or more functional groups. These groups are also referred to as "polymerizable groups" or "P". Unless otherwise stated, the term "polymerizable compound" as used herein is understood to mean a polymerizable monomeric compound. As used herein, the term "low molecular weight compound" should be understood to mean a compound that is monomeric and/or not prepared by polymerization, as opposed to a "polymeric compound" or "polymer." The term "halogen" means fluorine, chlorine or bromine, preferably fluorine or chlorine and especially fluorine. The term halogenation is used analogously. As used herein, the term "non-polymerizable compound" is understood to mean a compound that does not contain functional groups suitable for polymerization under conditions typically applied in RM polymerization reactions. The term "mesogene" is known to those skilled in the art and described in the literature, and means a liquid crystal (LC) in low molecular weight or polymeric substances that essentially contributes to the formation of liquid crystals (LC) in low molecular weight or polymeric materials due to the anisotropy of their attractive and repulsive interactions. Phase generating group. The compound containing a mesogen (mesogen compound) does not need to have a liquid crystal phase itself. It is also possible that mesogen compounds exhibit liquid crystalline phase behavior only after mixing with other compounds and/or after polymerization. Typical mesogens are, for example, rigid rod-shaped or disk-shaped units. An overview of terms and definitions used in connection with mesogens or liquid crystal compounds is provided in Pure Appl. Chem. 73(5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, Given in 6340-6368. The term "spacer" or simply "spacer", also referred to as "Sp", above and below, is known to those skilled in the art and is described in the literature, see for example Pure Appl. Chem. 73(5) , 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. Unless otherwise indicated, the term "spacer group" or "spacer" above and below means a flexible group connecting the mesogen group and the polymerizable group to each other in the polymerizable mesogen compound. Although the mesogen group generally contains rings, the spacer group is generally an acyclic system, that is, in the form of a chain, where the chain can also be a branched chain. The term chain is used, for example, for alkylene groups. Substitutions such as -O- or -COO- are generally included both on and in the chain. In functional group terminology, a spacer (spacer group) is a linking group between functional structural parts of a molecule that contributes to specific steric flexibility between such parts. In a preferred embodiment, the spacer group represents an alkylene group (such as -(CH ₂ ) _n - and n=1 to 10) or an alkyleneoxy group, preferably having 2 to 5 carbon atoms. Above and below, represents trans-1,4-cyclohexyl ring, and Represents 1,4-phenylene ring. For the purposes of the present invention, the term "liquid-crystalline medium" is intended to mean a medium comprising a liquid crystal mixture and one or more polymerizable compounds such as, for example, Formula I or reactive mesogens. The term "liquid crystal mixture" (or "host mixture") is intended to mean consisting solely of non-polymerizable low molecular weight compounds, preferably two or more liquid crystal compounds and optionally other additives such as chiral dopants Or a liquid crystal mixture composed of stabilizers. Particularly preferred are liquid crystal mixtures and liquid crystal media having a nematic phase, especially a nematic phase at room temperature. Furthermore, there are preferred embodiments of additives of formula I. Preferably, m1 in Formula I is 0 or 1, with 0 being the best. More preferred is a compound of formula I selected from the group of compounds of the following formula, wherein T is a group selected from the group of the following formula Wherein R ^{a , b , c , d} are independently linear or branched chain alkyl groups having 1 to 10 C atoms. Preferably, Z ¹ in formula I represents -CO-O-, -O-CO- or a single bond, preferably -CO-O- or a single bond. Preferably, Z ² and Z ³ in formula I represent -CO-O-, -O-CO- or a single bond, preferably a single bond. Preferably, P in formula I is an acrylate or methacrylate group. Preferably, Sp in formula I is a single bond. Preferably, A ³ in Formula I represents an aromatic group or a heteroaromatic group with 6 to 24 ring atoms, which may also contain a fused ring and optionally be substituted by one or more groups L. Advantageously, A ³ in formula I represents benzene or naphthalene, optionally substituted by one or more groups L. Preferably, A ¹ and A ² in formula I represent an aromatic group or a heteroaromatic group with 6 to 24 ring atoms, which may also contain a fused ring and optionally pass through one or more groups L or R -(A ³ -Z ³ ) _m2 -substituted, or A ¹ is a single bond. Advantageously, A ¹ and A ² in formula I represent benzene, cyclohexylene, naphthalene, phenanthrene or anthracene, optionally substituted by one or more groups L or R-(A ³ -Z ³ ) _m2 - , or A ¹ is a single bond. Preferably, -(A ² -Z ² -A ¹ ) _m1 - in formula I represents benzene, diphenyl, p-triphenyl (1,4-diphenylbenzene), meta-triphenyl (1,3 -diphenylbenzene), naphthyl, 2-phenyl-naphthyl, phenanthrene or anthracene, all of which are optionally substituted by one or more groups L. Preferably, -(A ² -Z ² -A ¹ ) _m1 - represents biphenylene, p-biphenylene or meta-biphenylene, each of which is optionally substituted by one or more groups L. The preferred group -(A ² -Z ² -A ¹ ) _m1 - is selected from the following formula wherein L is as defined in formula I or has one of the preferred meanings as described above and below, r is 0, 1, 2, 3 or 4, s is 0, 1, 2 or 3, and t is 0, 1 or 2 and u is 0, 1, 2, 3, 4 or 5. Particularly preferred are groups of the formulas A1, A2, A3, A4 and A5. Preferred compounds of formula I are selected from the following sub-formulas wherein P, Sp, R ^{a - d} , Z ¹ , L and R are as defined in formula I or have one of the preferred meanings as described above and below, and Re ^is an alkyl group having 1 to 12 C atoms , r is 0, 1, 2, 3 or 4 and s is 0, 1, 2 or 3. Preferably, Z ¹ in formula I and I-1 to I-45 represents -CO-O-, -O-CO- or a single bond, preferably -CO-O- or a single bond. Preferably, P in formula I and I-1 to I-45 is acrylate or methacrylate. Preferably, Sp in formula I and I-1 to I-45 is a single bond. Preferably, R ^a , R ^b , R ^c and R ^d in formula I and I-1 to I-45 are methyl groups. Preferably, R ^g in formula I is H. Preferred structures among I-1 to I-45 are structures I-1 and I-23, especially structure I-23. More preferred compounds of formula I and its subformulas I-1 to I-45 are independently selected from the following preferred embodiments, including any combination thereof: - these compounds contain exactly one polymerizable group (denoted as group P ), - P is acrylate or methacrylate, - Sp is a single bond, - Sp is selected from -(CH ₂ ) _a -O-, -(CH ₂ ) _a -CO-O- when it is different from a single bond , -(CH ₂ ) _a - and -(CH ₂ ) _a -O-CO-, where 2, 3, 4, 5 or 6, as applicable, and the O atom or CO- group is respectively connected to the next ring A2 Or group T, - R ^a , R ^b , R ^c and R ^d are methyl, - R ^e is methyl, ethyl, n-propyl, isopropyl, tert-butyl, n-butyl or n-pentyl base, - R ^g is H, - m1 is 0, 1 or 2, - m2 is 0, 1 or 2, - Z ¹ represents -CO-O-, -O-CO- or a single bond, preferably -CO -O-, - Z ² represents -CO-O-, -O-CO- or a single bond, preferably a single bond, - L represents F, Cl, CN or fluorine as appropriate with 1 to 6 C atoms _{The alkyl or alkoxy group} of T, - r is 0 or 1, - s is 0, - t is 0 - u is 0, 1 or 2. In a preferred embodiment of the present invention, the liquid crystal medium contains one or more dielectrically positive compounds with a dielectric anisotropy greater than 3, which are selected from the group of compounds of formulas II-1 and II-2: wherein the parameters have their respective meanings as indicated above according to formula II, and L ²³ and L ²⁴ independently represent H or F, preferably, L ²³ represents F, and And in the case of formula II-1 and II-2, X ² preferably represents F or OCF ₃ , particularly preferably represents F, and in the case of formula II-2, And/or selected from the group of compounds of formula III-1 and III-2: wherein the parameters have the meanings given according to formula III, and as an alternative to or in addition to the compounds of formula III-1 and/or III-2, the medium according to the invention may comprise one or more compounds of formula III-3 compound, wherein the parameters have their respective meanings as indicated above, and parameters L ³¹ and L ³² represent H or F independently of each other and independently of the other parameters. The liquid crystal medium preferably contains a compound selected from the group of compounds of formulas II-1 and II-2, wherein L ²¹ and L ²² and/or L ²³ and L ²⁴ both represent F. In a preferred embodiment, the liquid crystal medium includes a compound selected from the group of compounds of formulas II-1 and II-2, wherein L ²¹ , L ²² , L ²³ and L ²⁴ all represent F. The liquid crystal medium preferably contains one or more compounds of formula II-1. The compound of formula II-1 is preferably selected from the group of compounds of formula II-1a to II-1e, preferably formula II-1a and/or II-1b and/or II-1d, preferably one or more formulas II-1a and/or II-1d or II-1b and/or II-1d, preferably the compound of formula II-1d: wherein the parameters have the respective meanings indicated above, and the parameters L ²⁵ and L ²⁶ represent H or F independently of each other and independently of the other parameters, and preferably in formulas II-1a and II-1b, L ²¹ and L ²² both represent F, in formula II-1c and II-1d, L ²¹ and L ²² both represent F, and/or L ²³ and L ²⁴ both represent F, and in formula II-1e, L ²¹ , L ²² and L ²³ represent F. The liquid crystal medium preferably contains one or more compounds of formula II-2, and these compounds are preferably selected from the group of compounds of formulas II-2a to II-2k, preferably one or more compounds of formulas II-2a, II-2h, Compounds of each of II-2k and/or II-2j: The parameters have the respective meanings indicated above, and L ²⁵ to L ²⁸ independently represent H or F. Preferably, L ²⁷ and L ²⁸ both represent H, and particularly preferably, L ²⁶ represents H. The liquid crystal medium preferably contains a compound selected from the group of compounds of formulas II-2a to II-2k, wherein both L ²¹ and L ²² represent F, and/or both L ²³ and L ²⁴ represent F. In a preferred embodiment, the liquid crystal medium includes a compound selected from the group of compounds of formulas II-2a to II-2k, wherein L ²¹ , L ²² , L ²³ and L ²⁴ all represent F. Particularly preferred compounds of formula II-2 are compounds of the following formula, particularly preferred compounds of formula II-2a-1, II-2h-1 and/or II-2k-1 and/or II-2j--1 Compounds: wherein R ² and X ² have the meanings indicated above, and X ² preferably represents F. The liquid crystal medium preferably contains one or more compounds of formula III-1. The compound of formula III-1 is preferably selected from the group of compounds of formula III-1a to III-1j, preferably selected from the group of compounds of formula III-1c, III-1f, III-1g and III-1k: wherein the parameters have the meanings given above, and preferably wherein the parameters have the respective meanings indicated above, the parameters L ³³ and L ³⁴ represent H or F independently of each other and independently of the other parameters, and the parameter L ³⁵ and L ³⁶ represent H or F independently of each other and other parameters. The liquid crystal medium preferably contains one or more compounds of formula III-1c. These compounds are preferably selected from the group of compounds of formulas III-1c-1 to III-1c-5, preferably formulas III-1c-1 and/or Or a compound of III-1c-2, preferably a compound of formula III-1c-1: wherein R ³ has the meaning indicated above. The liquid crystal medium preferably contains one or more compounds of formula III-1f. These compounds are preferably selected from the group of compounds of formulas III-1f-1 to III-1f-6, preferably formulas III-1f-1 and/or Or compounds of III-1f-2 and/or III-1f-3 and/or III-1f-6, more preferably compounds of formula III-1f-3 and/or III-1f-6, more preferably compounds of formula III Compounds of -1f-6: wherein R ³ has the meaning indicated above. The liquid crystal medium preferably contains one or more compounds of formula III-1g. These compounds are preferably selected from the group of compounds of formula III-1g-1 to III-1g-5, and are preferably compounds of formula III-1g-3: wherein R ³ has the meaning indicated above. The liquid crystal medium preferably contains one or more compounds of formula III-1h. These compounds are preferably selected from the group of compounds of formula III-1h-1 to III-1h-3, and are preferably compounds of formula III-1h-3. : The parameters have the meanings given above, and X ³ preferably represents F. The liquid crystal medium preferably contains one or more compounds of formula III-1i. These compounds are preferably selected from the group of compounds of formula III-1i-1 and III-1i-2, and are preferably compounds of formula III-1i-1. : The parameters have the meanings given above, and X ³ preferably represents F. The liquid crystal medium preferably contains one or more compounds of formula III-1j. These compounds are preferably selected from the group of compounds of formula III-1j-1 and III-1j-2, and are preferably compounds of formula III-1j-1. : The parameters have the meaning given above. The liquid crystal medium preferably contains one or more compounds of formula III-1k. These compounds are preferably selected from the group of compounds of formula III-1k-1 and III-1k-2, and are preferably compounds of formula III-1k-1. : The parameters have the meaning given above. The liquid crystal medium preferably contains one or more compounds of formula III-2. The compound of formula III-2 is preferably selected from the group of compounds of formula III-2a and III-2b, and is preferably a compound of formula III-2b: wherein the parameters have their respective meanings as indicated above, and parameters L ³³ and L ³⁴ represent H or F independently of each other and independently of the other parameters. The liquid crystal medium preferably contains one or more compounds of formula III-2a, and these compounds are preferably selected from the group of compounds of formulas III-2a-1 to III-2a-6: wherein R ³ has the meaning indicated above. The liquid crystal medium preferably contains one or more compounds of formula III-2b. These compounds are preferably selected from the group of compounds of formula III-2b-1 to III-2b-4, and are preferably compounds of formula III-2b-4. : wherein R ³ has the meaning indicated above. And as an alternative to or in addition to the compounds of formula III-1 and/or III-2, the medium according to the invention may comprise one or more compounds of formula III-3, The parameters have the respective meanings indicated above according to Formula III. These compounds are preferably selected from the group of formulas III-3a and III-3b: wherein R ³ has the meaning indicated above. In a more preferred embodiment, the liquid crystal medium further includes one or more compounds of formula III-1h-3 and one or more compounds of formula III-1j-1 in addition to the compound of formula I and the compound of formula II. The liquid crystal medium according to the present invention preferably contains one or more dielectrically neutral compounds with dielectric anisotropy in the range of -1.5 to 3. In this application, such elements include their respective isotopes. In particular, one or more H's in these compounds may be replaced by D, and in some embodiments, this is also particularly preferred. A correspondingly high degree of deuteration of the corresponding compounds enables, for example, the detection and identification of these compounds. In some cases this is extremely helpful, especially in the case of compounds of formula I. In this application, alkyl particularly preferably means a straight-chain alkyl group, especially CH ₃ -, C ₂ H ₅ -, n -C ₃ H ₇ -, n -C ₄ H ₉ - or n -C ₅ H ₁₁ -, and alkenyl group preferably represents CH ₂ =CH-, E -CH ₃ -CH=CH-, CH ₂ =CH-CH ₂ -CH ₂ -, E -CH ₃ -CH=CH-CH ₂ -CH ₂ - or E -( n -C ₃ H ₇ )-CH=CH-. In another preferred embodiment, the medium contains one or more compounds of formula IV-A Wherein R ⁴¹ represents an unsubstituted alkyl group with 1 to 7 C atoms or an alkyl group with 2 to 7 C atoms, preferably n-alkyl group, especially preferably with 2, 3, 4 or 5 C atoms. Unsubstituted alkenyl, and R ⁴² represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkenyl group having 2 to 7 C atoms, or an unsubstituted alkenyl group having 1 to 6 C atoms. Substituted alkoxy group, wherein the group preferably has 2 to 5 C atoms, and is preferably an unsubstituted alkenyl group with 2, 3 or 4 C atoms, more preferably vinyl or 1-propene base, and especially vinyl. In a particularly preferred embodiment, the medium contains one or more compounds of formula IV selected from the group of compounds of formulas IV-1 to IV-4, preferably compounds of formula IV-1, Wherein alkyl and alkyl', independently represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and alkenyl and alkenyl', independently represent an alkyl group having 2 to 5 C atoms Atoms, preferably alkenyl having 2 to 4 C atoms, especially preferably 2 C atoms, alkenyl' preferably means having 2 to 5 C atoms, preferably 2 to 4 C atoms, especially more Preferred are alkenyl groups having 2 to 3 C atoms, and alkoxy groups represent alkoxy groups having 1 to 5 C atoms, preferably 2 to 4 C atoms. In a particularly preferred embodiment, the medium according to the invention contains one or more compounds of formula IV-1 and/or one or more compounds of formula IV-2. In another preferred embodiment, the medium contains one or more compounds of formula V. The medium according to the invention preferably contains the following compounds in a total concentration as indicated below: 0.001-1% by weight of one or more compounds of the formula I, 5-60% by weight of one or more compounds of the formula II, preferably selected from the group consisting of the formula The group of compounds of II-1 and II-2, and/or 5-25% by weight of one or more compounds of formula III, and/or 5-60% by weight of one or more compounds of formula IV, and/or 3-25 % by weight of one or more compounds of formula V, wherein the total content of all compounds of formula I and compounds of formulas II to V (which are present in the medium) is preferably 95% or higher, more preferably 97% or higher, and Best is 100%. The conditions for total content preferably apply to all media according to this application. In another preferred embodiment, the medium according to the invention further preferably contains one or more dielectrically neutral compounds, which compounds are preferably selected from the group consisting of a total concentration of 5% or higher to 90% or lower, and more The group of compounds of formulas IV and V is preferably in the range of 10% or higher to 80% or lower, particularly preferably 20% or higher to 70% or lower. In a particularly preferred embodiment, the medium according to the invention contains: one or more total concentrations in the range of 15% by weight or more to 65% or less, preferably 30% or more to 55% or a compound of formula II in a lower range, and/or one or more compounds of formula III in a total concentration in the range of 5% or higher to 30% or lower. In a preferred embodiment of the present invention, the concentration of the compound of formula II in the medium is 15% by weight or higher to 65% or lower, more preferably 15% or higher to 60% or lower, more preferably 20% by weight. % or higher to 55% or lower, and preferably in the range of 25% or higher to 40% or lower. The invention also relates to electro-optical displays or electro-optical components containing a liquid crystal medium according to the invention. Preference is given to electro-optical displays based on the IPS or FFS effect, preferably based on the IPS effect, and in particular displays addressed by means of active matrix addressing means. The invention therefore also relates to the use of a liquid-crystalline medium according to the invention in electro-optical displays or in electro-optical components, and to a method for preparing a liquid-crystalline medium according to the invention, characterized in that one or more compounds of the formula I are combined with One or more compounds of formula II are mixed with optional other compounds and additives. In another preferred embodiment, the medium contains one or more compounds of formula IV selected from the group of compounds of formulas IV-2 and IV-3, Wherein alkyl and alkyl' independently represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and alkoxy group represents an alkyl group having 1 to 5 C atoms, preferably 2 to 5 C atoms. Alkoxy group with 4 C atoms. In another preferred embodiment, the medium contains one or more compounds of formula V, which are selected from the group of compounds of formula V-1 and V-2, preferably formula V-1, wherein the parameters have the meanings given above according to formula V, and preferably, R ⁵¹ represents an alkyl group having 1 to 7 C atoms or an alkenyl group having 2 to 7 C atoms, and R ⁵² represents a group having 1 An alkyl group with 7 C atoms, an alkenyl group with 2 to 7 C atoms, or an alkoxy group with 1 to 6 C atoms is preferably an alkyl group or an alkenyl group, and particularly preferably an alkyl group. In another preferred embodiment, the medium contains one or more compounds of formula V-1 selected from the group of compounds of formulas V-1a and V-1b, Wherein alkyl and alkyl' independently represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and alkenyl represents an alkyl group having 2 to 7 C atoms, preferably 2 to 5 C atoms. Alkenyl group with 5 C atoms. In addition to the compounds of the formulas I to V, other ingredients may also be present, for example in an amount of up to 45% of the total mixture, but preferably up to 35%, especially up to 10%. The medium according to the present invention may optionally contain a dielectric negative component, and its total concentration based on the entire medium is preferably 20% or lower, more preferably 10% or lower. In a preferred embodiment, based on the total mixture, the liquid crystal medium according to the present invention contains a total of 25% or higher to 65% or lower, preferably 30% or higher to 60% or lower, especially preferably 35% or more to 55% or less of the compounds of formula II and/or III, and 5% or more to 60% or less, preferably 25% or more to 55% or less, especially more Preferably 35% or more to 55% or less of compounds of formula IV and/or V. Liquid-crystalline media according to the invention may contain one or more chiral compounds. Particularly preferred embodiments of the invention satisfy one or more of the following conditions, wherein the acronyms (abbreviations) are explained in Tables A to C and are illustrated by the examples in Table D. Preferably, the medium according to the present invention satisfies one or more of the following conditions. i. The birefringence of the liquid crystal medium is 0.060 or higher, especially preferably 0.070 or higher. ii. The birefringence of the liquid crystal medium is 0.200 or lower, especially preferably 0.180 or lower. iii. The birefringence of the liquid crystal medium is in the range of 0.090 or higher to 0.160 or lower. iv. The liquid crystal medium contains preferably one or more compounds of formula I selected from (sub)formulas I-1 and I-23, the best (sub)formula I-23, and particularly preferred compounds of formula I. v. The total concentration of the compound of formula II in the overall mixture is 25% or higher, preferably 30% or higher, and preferably in the range of 25% or higher to 49% or lower, especially preferably Within the range of 29% or higher to 47% or lower, and most preferably within the range of 37% or higher to 44% or lower. vi. The liquid crystal medium contains one or more compounds of formula IV selected from the group of compounds of the following formula: CC-nV and/or CC-n-Vm and/or CC-VV and/or CC-V-Vn and/or CC- nV-Vn, especially preferably CC-3-V, its concentration is preferably at most 60% or lower, especially preferably at most 50% or lower; and optionally additional CC-3-V1, which The concentration is preferably at most 15% or lower; and/or CC-4-V, the concentration is preferably at most 40% or lower, especially preferably at most 30% or lower. vii. These media contain compounds of formula CC-nV, preferably formula CC-3-V, preferably in a concentration of 1% or higher to 60% or lower, and preferably in a concentration of 3% or higher to 38 % or lower. viii. The total concentration of the compound of formula CC-3-V in the overall mixture is preferably 15% or lower, preferably 10% or lower, or 20% or lower, preferably 25% or higher . Furthermore, the invention relates to an electro-optical display with an active matrix based on IPS or FFS effect addressing, characterized in that it contains a liquid crystal medium according to the invention as a dielectric. The nematic phase range of the liquid crystal mixture preferably has a width of at least 70 degrees. The rotational viscosity γ ₁ is preferably 350 mPa·s or less, preferably 250 mPa·s or less, and especially 150 mPa·s or less. The mixtures according to the invention are suitable for all IPS and FFS-TFT applications using dielectrically positive liquid crystal media, such as SG-FFS. The liquid-crystalline medium according to the invention preferably consists almost entirely of 4 to 15 compounds, in particular 5 to 12 compounds and particularly preferably 10 compounds or less. These compounds are preferably selected from the group of compounds of formulas I, II, III, IV, V, VI, VII, VIII and IX. Liquid crystal media according to the invention may optionally contain more than 18 compounds. In this case, it preferably contains 18 to 25 compounds. In a preferred embodiment, the liquid-crystalline medium according to the invention mainly contains, preferably essentially consists of and most preferably almost entirely consists of cyano-free compounds. In a preferred embodiment, the liquid crystal medium according to the present invention comprises a group of compounds selected from formulas I, II and II, IV and V, preferably selected from the group consisting of formulas I, II-1, II-2, IV and V A compound of the group of compounds; it is preferably mainly composed of the compound of the formula, especially preferably it consists essentially of it and most preferably it consists almost entirely of it. The nematic phase of the liquid crystal medium according to the invention is in each case preferably at least -10°C or lower to 70°C or higher, particularly preferably -20°C or lower to 80°C or higher, extremely preferably Preferably it is -30°C or lower to 85°C or higher and most preferably -40°C or lower to 90°C or higher. The expression “having a nematic phase” means here that, on the one hand, no smectic phase and crystallization are observed at low temperatures at the corresponding temperatures, and, on the other hand, that no clearing occurs on heating from the nematic phase. Studies at low temperatures were carried out in flow viscometers at corresponding temperatures and verified by storage in test cells with cell thickness corresponding to the electro-optical application for at least 100 hours. If the storage stability at -20°C in the corresponding test unit is 1000 hours or more, the medium is considered stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours respectively. At high temperatures, the clear point is measured in the capillary tube by conventional methods. In a preferred embodiment, the liquid crystal medium according to the invention is characterized by optical anisotropy values in the medium to low range. The birefringence value is preferably in the range of 0.075 or higher to 0.130 or lower, particularly preferably in the range of 0.085 or higher to 0.120 or lower and extremely preferably in the range of 0.090 or higher to 0.115 or lower within the range. In this embodiment, the liquid crystal medium according to the present invention has positive dielectric anisotropy and a relatively high absolute value of dielectric anisotropy Δε, which is preferably between 9.0 or higher and 22 or lower, and more preferably between 18 or lower, preferably 10 or higher to 15 or lower, particularly preferably 4.0 or higher to 9.0 or lower, and extremely preferably 4.5 or higher to 8.0 or lower. The liquid crystal medium according to the present invention preferably has a relatively low threshold voltage (V ₀ ) value, which is between 1.0 V or higher and 5.0 V or lower, preferably 2.5 V or lower, preferably 1.2 V or lower. Higher to 2.2 V or lower, particularly preferably 1.3 V or higher to 2.0 V or lower. In addition, the liquid crystal medium according to the present invention has a higher VHR value in the liquid crystal cell. The VHR value of these media is greater than or equal to 95%, preferably greater than or equal to 97%, particularly preferably greater than or equal to 98% and extremely preferably greater than or equal to 99% in a newly filled cell at 20°C. , and after 5 minutes in the oven at 100°C in the unit, these VHR values are greater than or equal to 90%, preferably greater than or equal to 93%, especially preferably greater than or equal to 96% and extremely preferably greater than or equal to 98%. In general, liquid crystal media having a low addressing voltage or threshold voltage are herein described to have a lower VHR than those having a higher addressing voltage or threshold voltage, and vice versa. In each case, these preferred values of the individual physical properties are preferably also maintained by combining the media with one another according to the invention. In this application, unless otherwise expressly indicated, the term "compounds/compound(s)" means one and a plurality of compounds. In a preferred embodiment, the liquid crystal medium according to the present invention includes one or more formulas Compound I, preferably selected from the group of formulas I-1 and/or I-23, and/or one or more compounds of formula II, preferably selected from the group of formulas PUQU-nF, CDUQU-nF, APUQU-nF and PGUQU-nF and/or the group of CPUQU-nF, and/or one or more compounds of formula III, preferably selected from the group of formulas CCP-n-OT, CGG-nF and CGG-n-OD, and/or one or more compounds of formula IV and/or compounds of V, preferably selected from the group of formulas CC-nV, CCP-nm, CCP-Vn, CCP-V2-n and CGP-nn, and/or optionally preferably one or more Compounds of formula IV are preferably selected from the group consisting of formulas CC-nV, CC-n-Vm, CC-n-mVl and CC-nV-Vm, preferably CC-3-V, CC-3-V1, CC-4-V , the group of compounds of CC-5-V, CC-3-2V1 and CC-VV, especially preferably selected from the group consisting of compounds CC-3-V, CC-3-V1, CC-4-V, CC-3-2V1 and CC-VV, extremely preferably the compound CC-3-V, and optionally the compound CC-4-V and/or CC-3-V1 and/or CC-3-2V1 and/or CC- VV, and/or optionally preferably one or more compounds of formula V, preferably selected from the group of formulas CCP-V-1 and/or CCP-V2-1. For the present invention, unless in individual cases otherwise indicated below, otherwise the following definitions shall apply in conjunction with the description of the ingredients of the composition: - "Contains": the concentration of the ingredient in question in the composition is preferably 5% or higher, particularly preferably 10% or higher, and extremely Preferably 20% or more, - "consisting essentially of": the concentration of the ingredient in question in the composition is preferably 50% or more, particularly preferably 55% or more and extremely preferably 60% or more, - "consisting essentially of": the concentration of the ingredient in question in the composition is preferably 80% or more, particularly preferably 90% or more and most preferably 95% or more Higher, and - "consisting almost entirely of": The concentration of the ingredient in question in the composition is preferably 98% or higher, particularly preferably 99% or higher and very preferably 100.0%. This Also applies to a medium in the form of a composition with its constituents, which may be components and compounds, as well as components, compounds with its constituents. Only with respect to the concentration of the individual compounds relative to the medium as a whole, the term includes Meaning: The concentration of the compound in question is preferably 1% or higher, particularly preferably 2% or higher, extremely preferably 4% or higher. For the purposes of the present invention, "≤" means less than or equal to , preferably less than, and "≥" means greater than or equal to, preferably greater than. For the present invention Represents trans-1,4-cyclohexylene, represents a mixture of cis-1,4-cyclohexylene and trans-1,4-cyclohexylene, and Represents 1,4-phenylene group. For the present invention, the expression "dielectrically positive compound" means a compound with Δε > 1.5, the expression "dielectrically neutral compound" means such a compound with -1.5 ≤ Δε ≤ 1.5, and the expression "dielectrically negative compound" It means those compounds with Δε < -1.5. The host mixture used for measuring Δε was ZLI-4792 for dielectrically positive and dielectrically neutral compounds, and the host mixture for dielectrically negative compounds was ZLI-2857, both from Merck KGaA, Germany. The values for the individual compounds under investigation are obtained from the change in the dielectric constant of the bulk mixture after addition of the compound under investigation and extrapolated to 100% of the compound used. The compound to be studied is dissolved in an amount of 10% of the main mixture. If the solubility of the substance is too low for this purpose, the concentration is halved during the procedure until the study can be carried out at the required temperature. If necessary, the liquid crystal medium according to the present invention may further comprise conventional amounts of additives, such as stabilizers and/or polychromatic (eg bichromatic) dyes and/or chiral dopants. The additives are preferably used in a total amount of 0% or more to 10% or less, based on the total mixture, particularly preferably 0.1% or more to 6% or less. The concentrations of individual compounds used are preferably 0.1% or higher and 3% or lower. The concentration of these and similar additives is generally not considered when specifying the concentration and concentration range of liquid crystal compounds in a liquid crystal medium. In a special embodiment, the liquid crystal medium according to the present invention may include a polymer precursor, which includes one or more reactive compounds, preferably reactive mesogens, and if necessary, the liquid crystal medium further includes commonly used amount of additives such as polymerization initiators and/or polymerization moderators. The amount of these additives used totals 0% or more to 10% or less, preferably 0.1% or more to 2% or less, based on the total mixture. The concentrations of these and similar additives are not taken into account when specifying concentrations and concentration ranges of liquid crystal compounds in liquid crystal media. Such compositions consist of a plurality of compounds mixed in a conventional manner, preferably 3 or more to 30 or less, particularly preferably 6 or more to 20 or less, and extremely preferably 10. or more to 16 or less compounds. Generally, the required amount of the component used in smaller amounts is dissolved in the components constituting the main component of the mixture. This is advantageously carried out at high temperatures. The completion of the dissolution operation is particularly easy to observe if the selected temperature is higher than the clearing point of the main component. However, it is also possible to prepare the liquid crystal mixture in other conventional ways, such as using a premix or a so-called "multi-bottle system". Mixtures according to the invention exhibit a very wide nematic range with a clearing point of 65°C or higher, a very favorable capacitance threshold, a relatively high retention value and are excellent at -30°C and -40°C at the same time The low temperature stability. Furthermore, the mixtures according to the invention are distinguished by a low rotational viscosity γ ₁ . It goes without saying to those skilled in the art that the medium according to the present invention may also contain compounds in which, for example, H, N, O, Cl, F have been replaced with corresponding isotopes. The structure of the IPS liquid crystal display according to the present invention corresponds to commonly used geometric structures, as described for example in US 2001022569 A or US 2002030782 A. The liquid crystal phase according to the invention can be modified by means of suitable additives in such a way that it can be used, for example, in any type of IPS and FFS LCD displays that have been disclosed so far. Table E below indicates possible dopants that may be added to the mixture according to the invention. If the mixture contains one or more dopants, the amount is from 0.01% to 4%, preferably from 0.1% to 1.0%. Additional stabilizers which may be added, for example, to the mixture according to the invention are preferably shown in Table F below in an amount of 0.001% to 6%, especially 0.1% to 3%. In a preferred embodiment of the present invention, the liquid crystal medium additionally contains a stabilizer selected from phenols, more preferably selected from derivatives of 2,6-di-tert-butylphenol, which is preferably listed in Table F below. The phenols listed in are preferably selected from the group of formulas S-1 and S-2: Where R ^S represents an alkyl group, alkoxy group, fluorinated alkyl group or fluorinated alkoxy group with 1 to 9 C atoms, an alkenyl group, alkenyloxy group, alkoxyalkyl group with 2 to 9 C atoms. base. Particularly preferred structures of formula S-1 or S-2 are compounds of formula S-1-3 and S-2-3: For the purposes of this invention, all concentrations are indicated in weight percent and, unless expressly stated otherwise, relate to the respective overall mixture or total mixture component. In this context, the term "mixture" describes a liquid crystalline medium. Unless otherwise expressly indicated, all temperature values indicated in this application, such as melting point T(C,N), phase transition T(S,N) from smectic (S) to nematic (N), and clarity Points T(N,I), are indicated in degrees Celsius (°C), and all temperature differences are correspondingly indicated in degrees of difference (° or degrees). For the present invention, unless otherwise explicitly indicated, the term "threshold voltage" refers to the capacitance threshold (V ₀ ), also known as the Freedericks threshold. Unless otherwise expressly indicated in each case, all physical properties are and have been determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status November 1997, Merck KGaA, Germany and apply at a temperature of 20°C, And Δn is measured at 436 nm, 589 nm and 633 nm and Δε is measured at 1 kHz. In this context, the dielectric anisotropy of a compound is determined by dissolving 10% of the compound in a liquid crystal host and in each case determining the capacitance of the resulting mixture in at least one test cell, the unit of which 20 µm thick with vertical and uniform surface alignment at 1 kHz. The measured voltages were typically 0.3 V to 1.0 V, but were always below the capacitance threshold of the respective liquid crystal mixtures studied. The threshold voltage and all other electro-optical characteristics are determined using test units produced by Merck. The cell thickness of the test cell used to determine Δε was approximately 20 µm. The electrode is a circular ITO electrode with an area of 1.13 ^cm2 and a protective ring. The alignment layers were SE-1211 from Nissan Chemicals, Japan for vertical orientation (ε _|| ) and polyimide AL-1054 from JSR, Japan for homogeneous orientation (ε _⊥ ). Use a Solatron 1260 frequency response analyzer to measure capacitance using a sine wave with a voltage of 0.3 V _rms . The light used for electro-optical measurement is white light. Equipment utilizing a DMS instrument commercially available from Autronic-Melchers, Germany was used in this paper. The characteristic voltage has been determined under vertical observation. Threshold (V ₁₀ ), mid-grey (V 50 ) and saturation (V ₉₀ ) voltages were measured for 10%, ₅₀ % and 90% relative contrast respectively. Unless otherwise indicated, chiral dopants are not added to the liquid crystal mixtures used, although the latter are particularly suitable for applications requiring such doping. Rotational viscosity is measured using the rotating permanent magnet method and flow viscosity in a modified Ubbelohde viscometer. For the liquid crystal mixtures ZLI-2293, ZLI-4792 and MLC-6608 (all products from Merck KGaA, Darmstadt, Germany), the rotational viscosity values measured at 20°C were 161 mPa·s, 133 mPa·s and 186 mPa respectively. ·s, and the flow viscosity values (ν) are 21 mm ² ·s ^{- 1} , 14 mm ² ·s ^{- 1} and 27 mm ² ·s ^{- 1} respectively. Unless otherwise expressly stated, for practical purposes the dispersion of a material may conveniently be characterized in the following manner as used throughout this application. Birefringence values are measured at a temperature of 20°C and at several fixed wavelengths using a modified Abbé refractometer with a vertically aligned surface on the side contacting the material. Birefringence values at specific wavelengths 436 nm (spectral line of individually selected low-pressure mercury lamps), 589 nm (sodium "D" line) and 633 nm (HE-Ne laser (in combination with attenuator/diffuser) Measured at a wavelength that is designed to prevent damage to the observer's eyes. In the table below, Δn is given at 589 nm and Δ(Δn) is given as Δ(Δn) = Δn(436 nm) - Δn(633 nm). Unless otherwise explicitly indicated, the following symbols are used: V ₀ threshold voltage, capacitance [V] at 20°C, n _e Abnormal refractive index measured at 20°C and 589 nm, n _o at 20°C and 589 nm Ordinary refractive index measured below, Dn Optical anisotropy measured at 20°C and 589 nm, λ Wavelength λ [nm], Dn(λ) Optical anisotropy measured at 20°C and wavelength λ, D(Dn) is the change in optical anisotropy defined as follows: Dn(20℃, 436 nm) - Dn(20℃, 633 nm), D(Dn*) is the "relative change in optical anisotropy" as defined below : D(Dn)/Dn(20℃, 589 nm), e _^ at 20℃ and 1 kHz, perpendicular to the dielectric susceptibility of the director, e _÷÷ at 20℃ and 1 kHz, parallel to the direction Arrow dielectric susceptibility, De dielectric anisotropy at 20°C and 1 kHz, T(N,I) or clp. Clear point [°C], n Flow viscosity measured at 20°C [mm ² ·s ^{- 1} ], g ₁ rotational viscosity at 20°C [mPa·s], k ₁₁ elastic constant, "tilt" deformation at 20°C [pN]; k ₂₂ elastic constant, "tilt" deformation at 20°C Torsional deformation [pN], elastic constant k ₃₃ , bending deformation [pN] at 20°C, LTS Low temperature stability of the phase measured in the test cell, VHR voltage retention rate ( VHR ), DVHR voltage retention rate of reduction, and the relative stability of S _rel VHR. The following examples are used to illustrate the present invention without limiting it. However, it is intended to demonstrate to those skilled in the art the concept of preferred mixtures and the compounds preferred to be used, their respective concentrations and their combinations with each other. In addition, examples illustrate available properties and combinations of properties. For the purposes of the present invention and in the following examples, the structures of the liquid crystal compounds are indicated by means of acronyms, the conversion of the chemical formulas being carried out according to Tables A to C below. All the groups C _n H _{2n + 1} , C _m H _{2m + 1} and C _l H _{2l + 1} or C _n H _2n , C _m H _2m and C _l H _2l are linear alkyl or alkylene groups, in In each case there are n, m and l C atoms respectively. Preferably, n, m and l are 1, 2, 3, 4, 5, 6 or 7 independently of each other. Table A shows the coding of the ring elements of the nucleus of the compound, Table B lists the bridging units, and Table C lists the meanings of the symbols of the left and right end groups of the molecule. The acronym consists of the code of the cyclic element with optional linking groups, followed by the code of the first hyphen and the left-hand end group, and the second hyphen and the code of the right-hand end group. Table D shows the illustrative structures of the compounds along with their respective abbreviations. Table A : Ring Elements Table B : Bridge Unit Table C : Terminal group where n and m are each an integer, and the three dots "..." are placeholders for other abbreviations from this table. In addition to the compound of formula B, the mixture according to the invention preferably contains one or more compounds as described below. The following abbreviations are used: (n, m, k and l are each independently an integer, preferably 1 to 9, preferably 1 to 7, k and l may also be 0, and preferably 0 to 4, More preferably, it is 0 or 2, and most preferably is 2, n is preferably 1, 2, 3, 4 or 5, in the combination "-nO-", it is preferably 1, 2, 3 or 4, preferably 2 or 4, m is preferably 1, 2, 3, 4 or 5, in the combination "-Om" it is preferably 1, 2, 3 or 4, more preferably 2 or 4. The combination "-lVm" is more Preferably "2V1".) Table D Exemplary and preferred dielectric positive compounds Exemplary, preferred dielectrically neutral compounds Table E shows preferred chiral dopants for use in mixtures according to the present invention. Table E In a preferred embodiment of the invention, the medium according to the invention contains one or more compounds selected from the group of compounds in Table E. Table F shows, in addition to the compounds of formula I, stabilizers which may also be preferably used in the mixtures according to the invention. The parameter n in this article represents an integer in the range of 1 to 12. In particular, the phenol derivatives shown can be used as additional stabilizers due to their role as antioxidants. Table F where n is 1, 2, 3, 4, 5, 6 or 7 independently of each other. Examples The following examples illustrate the invention without limiting it in any way. However, the physical properties allow those skilled in the art to understand what properties can be achieved and to what extent they can be modified. In particular, those skilled in the art are well aware of the combinations of properties that can be best achieved. The following polymerizable stabilizers (polymerizable piperidine derivatives) are used: Source: Santa Cruz Biotechnology Inc. (CAS 31582-45-3) Synthesis Examples of Additives Exemplary compounds of formula I are synthesized as follows or according to WO 2016/116119 A1 (Examples). Synthesis Example Compound RH - 2 was prepared as follows. 4-HydroxyTEMPO (8.00 g, 45.5 mmol) and 4-(dimethylamino)pyridine (0.30 g, 2.46 mmol) were added to 100 ml DCM. After cooling to 2°C, triethylamine (25.00 ml, 180.35 mmol) was added to the above solution, followed by 3-bromo-propionyl chloride (6.00 ml, 50.6 mmol) added dropwise to 50 ml DCM. After the addition was complete, the reaction mixture was allowed to warm to room temperature. After completion of conversion indicated by TLC, aqueous ammonium chloride solution was added. Extract the aqueous phase with DCM. The organic phases were combined, dried over anhydrous sodium sulfate and filtered. After removing the solvent in vacuo, the solid residue was purified by silica column chromatography using DCM/methyl tert-butyl ether (MTBE) 95:5 as eluent, and further recrystallized from heptane/MTBE to obtain 3 as red crystals (4.2 g, mp 102℃). ¹ H-NMR (CDCl ₃ , 500 MHz): d (ppm): 6.54 (br. m., 1 H, H _olefins ), 6.24 (br. m., 1 H, H _olefins ), 6.00 (br. m ., 1 H, H _olefins ), MS (EI ⁺ ) m/z: [M] ⁺ calculated for C ₁₂ H ₂₀ NO ₃ : 226.3; found 226.1. Additional stabilizers As additional stabilizers it is advantageous to use compounds selected from structures S-1-3 or S-2-3, which have the following structures: Examples of Mixtures The following host mixtures H1 to H4 were used to produce examples according to the invention: H1 : Nematic host - mixture H2 : Nematic host - mixture H3 : Nematic host - mixture H4 : Nematic host - mixture Comparative Example A Mixture (A) was prepared by mixing main mixture H1 with 0.05% by weight of non-polymerizable stabilizer S-1-3. The mixtures were studied in terms of voltage retention before and after the backlight load test. Mixture Example 1 To mixture (A) of Comparative Example (A) was added the polymerizable additive RH-1 at a concentration of 0.01% by weight. Mixture Example 2 To mixture (A) of Comparative Example (A) was added the polymerizable additive RH-2 at a concentration of 0.01% by weight. VHR Measurements : Effect of Polymerizable Piperidine Derivatives under Backlight Loading Test cells with (a) rubbed polyimide and (b) with photo-aligned polyimide were filled with the media of the previous examples. For (a) and (b) (Tables 1 and 2), the voltage retention rate (VHR) of the test unit was measured before and after intensive light load (120 min). The illumination light is equivalent to 500 h of a typical white CCFL backlight used in displays. Table 1: Results of rubbing polyimide (OPTMER® AL16301, JSR Corp.): *BL = Backlight load test; 120 h accelerated LED-based backlight Table 2: Results of light-aligned polyimide: *BL = Backlight Load Test; 120 h Accelerated LED Based Backlight Comparative Example B Mixture (B) was prepared by mixing host mix H1 with 0.05 wt% of non-polymerizable stabilizer S-2-3. The mixtures were studied in terms of voltage retention before and after the backlight load test. Mixture Example 3 To mixture (B) of Comparative Example (B) was added the polymerizable additive RH-1 at a concentration of 0.01% by weight. Mixture Example 4 To mixture (B) of Comparative Example (B) was added the polymerizable additive RH-2 at a concentration of 0.01% by weight. VHR measurement: Effect of polymerizable piperidine derivatives under backlight loading Test cells of (a) rubbed polyimide and (b) photo-aligned polyimide were filled with the media of the previous examples, and VHR was measured as above (Tables 3 and 4). Table 3: Results of rubbing polyimide (OPTMER® AL16301, JSR Corp.): *BL = Backlight load test; 144 h accelerated LED-based backlight Table 4: Results of light-aligned polyimide: *BL = Backlight load test; 120 h Accelerate LED-based backlighting by using polymerizable additives such as compounds of formula RH-1 or RH-2 to avoid VHR drop after backlight load. Test units filled with the mixtures of Examples 1 to 4 showed little reduction in VHR after backlight loading, while the comparative examples without any polymerizable additive (Examples A and B) showed a significant reduction in VHR.

Claims (13)

A liquid-crystalline medium having a nematic phase and a dielectric anisotropy (Δε) of 1.5 to 25, characterized in that it contains at least one polymerizable compound of formula I or a polymer containing its polymerized form, P-Sp-( A ² -Z ² -A ¹ ) _m1 -Z ¹ -TI in which the radicals independently of one another and on each occurrence the same or different have the following meaning T radicals selected from the following formulas

R ^g H or linear or branched chain alkyl or alkoxyalkyl with 1 to 10 C atoms, or benzyl, R ^a , R ^b , R ^c , R ^d have 1 to 10 C atoms Linear or branched alkyl, P vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane or epoxy group, Sp spacer group or single bond, A ¹ , A ² has an alicyclic group, heterocyclic group, aromatic group or heteroaromatic group with 4 to 30 ring atoms, which may also contain a fused ring and be unsubstituted or modified by one or more groups L or R -(A ³ -Z ³ ) _m2 -substituted, and one of A ¹ and A ² can also represent a single bond, A ³ has an alicyclic group, heterocyclic group, aromatic group with 4 to 30 ring atoms, or Heteroaromatic groups, which may also contain fused rings and are unsubstituted or substituted by one or more groups L, Z ¹ -O-, -S-, -CO-, -CO-O-, -O- CO-, -O-CO-O-, -OCH ₂ -, -CH ₂ O-, -SCH ₂ -, -CH ₂ S-, -CF ₂ O-, -OCF ₂ -, -CF ₂ S-, -SCF ₂ -, -(CH ₂ ) _n -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -(CF ₂ ) _n -, -CH=CH-, -CF=CF-, -CH= CF-, -CF=CH-, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH-, -CH ₂ -CH ₂ -CO-O-, -O- CO-CH ₂ -CH ₂ -, -CR ⁰⁰ R ⁰⁰⁰ - or single bond, the restriction condition is that if m1 is 0 and Sp is a single bond, then Z ¹ is a single bond, Z ² , Z ³ -O-, - S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -OCH ₂ -, -CH ₂ O-, -SCH ₂ -, -CH ₂ S-, - CF ₂ O-, -OCF ₂ -, -CF ₂ S-, -SCF ₂ -, -(CH ₂ ) _n -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -(CF ₂ ) _n - , -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- , -CH ₂ -CH ₂ -CO-O-, -O-CO-CH ₂ -CH ₂ -, -CR ⁰⁰ R ⁰⁰⁰ - or single bond, R ⁰⁰ , R ⁰⁰⁰ H or one with 1 to 12 C atoms Alkyl, R P-Sp-, H, F, Cl, CN or linear, branched or cyclic alkyl with 1 to 25 C atoms, in which one or more non-adjacent CH ₂ - groups are not Substituted by or by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O atoms and/or the S atoms are not directly connected to each other , and one or more of the H atoms are each not replaced by or replaced by F, Cl or P-Sp-, or R is a group selected from formulas 1, 2, 3 and 4, L P-Sp-, F, Cl , CN or straight chain, branched chain or cyclic alkyl group with 1 to 25 C atoms, in which one or more non-adjacent CH ₂ - groups are not or are composed of -O-, -S-, -CO- , -CO-O-, -O-CO-, -O-CO-O- are substituted in such a way that the O atoms and/or S atoms are not directly connected to each other, and one or more of the H atoms are each not or by F, Cl or P-Sp-substitution, or L is a group selected from formulas 1, 2, 3 and 4, m1 0, 1, 2, 3 or 4, m2 0, 1, 2, 3 or 4, and n 1, 2, 3 or 4, and 30% by weight to 55% by weight of one or more compounds selected from the group of compounds of formula II,

Where R ² represents an alkyl group, alkoxy group, fluorinated alkyl group or fluorinated alkoxy group with 1 to 7 C atoms, an alkenyl group, alkenyloxy group, alkoxyalkyl group with 2 to 7 C atoms. base or fluorinated alkenyl group,

and

represent independently of each other on each occurrence

or

L ²¹ and L ²² represent H or F, X ² represents halogen, a halogenated alkyl or alkoxy group having 1 to 3 C atoms or a halogenated alkenyl or alkenyloxy group having 2 or 3 C atoms, and m Represents 0, 1, 2 or 3. Such as the liquid crystal medium of claim 1, wherein m1 in formula I is 0 or 1. The liquid crystal medium of claim 1, wherein the compound of formula I is selected from the group of compounds of the following formula, wherein T is a group selected from the following

or

Wherein R ^a , R ^b , R ^c , R ^d are independently linear or branched chain alkyl groups having 1 to 10 C atoms. The liquid crystal medium of any one of claims 1 to 3, wherein it contains one or more compounds selected from the group of compounds of formula III,

Where R ³ represents an alkyl group, alkoxy group, fluorinated alkyl group or fluorinated alkoxy group with 1 to 7 C atoms, an alkenyl group, alkenyloxy group, alkoxyalkyl group with 2 to 7 C atoms. base or fluorinated alkenyl group,

and

independently of each other on each occurrence of

or

L ³¹ and L ³² independently represent H or F, and X ³ represents F, Cl, -OCF ₃ , -OCHF ₂ , -O-CH ₂ CF ₃ , -O-CH=CF ₂ , -O-CH= CH ₂ or -CF ₃ , Z ³ represents -CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -COO-, anti-CH=CH-, anti-CF=CF-, -CH ₂ O- or single bond , and n represents 0, 1, 2 or 3. The liquid crystal medium of any one of claims 1 to 3, wherein it contains one or more dielectric neutral compounds selected from the group of formula IV and formula V:

wherein R ⁴¹ and R ⁴² independently represent an alkyl group, an alkoxy group, a fluorinated alkyl group or a fluorinated alkoxy group having 1 to 7 C atoms, an alkenyl group or an alkenyl group having 2 to 7 C atoms. oxy, alkoxyalkyl or fluorinated alkenyl,

and

independently of each other and if

appear twice, they also represent independently of each other

or

Z ⁴¹ and Z ⁴² , independently of each other and if Z ⁴¹ appears twice, these also independently of each other represent -CH ₂ CH ₂ -, -COO-, anti-CH=CH-, anti-CF=CF-, -CH ₂ O-, -CF ₂ O-, -C≡C- or single bond, p represents 0, 1 or 2, R ⁵¹ and R ⁵² independently represent an alkyl group with 1 to 7 C atoms, Alkoxy, fluorinated alkyl or fluorinated alkoxy, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms,

to

If present, each represents independently of the other

or

Z ⁵¹ to Z ⁵³ each independently represent -CH ₂ -CH ₂ -, -CH ₂ -O-, -CH=CH-, -C≡C-, -COO- or a single bond, and i and j each represent each other Independently represents 0 or 1. The liquid crystal medium of claim 5, wherein it contains one or more compounds selected from the group of formula S-1 and formula S-2

where R ^S represents an alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy group having 1 to 9 C atoms, or an alkenyl, alkenyloxy or alkoxy group having 2 to 9 C atoms alkyl. The liquid crystal medium of any one of claims 1 to 3, wherein the total concentration of the compounds of Formula I in the medium as a whole is 0.001% by weight or higher to 0.05% by weight or lower. The liquid crystal medium of any one of claims 1 to 3, wherein it additionally contains one or more compounds of formula IV-A

wherein R ⁴¹ represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, and R ⁴² represents an unsubstituted alkenyl group having 1 to 7 C atoms. Alkyl, unsubstituted alkenyl having 2 to 7 C atoms or unsubstituted alkoxy having 1 to 6 C atoms. An electro-optical display or electro-optical component, characterized in that it contains the liquid crystal medium according to any one of claims 1 to 8. Such as the electro-optical display or electro-optical component of claim 9, wherein it is based on IPS mode or FFS mode. The electro-optical display or electro-optical component of claim 9 or 10, wherein it contains an active matrix addressing device. A use of the liquid crystal medium according to any one of claims 1 to 8, which is used in electro-optical displays or electro-optical components. A method for preparing a liquid-crystalline medium according to any one of claims 1 to 8, characterized in that one or more compounds of the formula I are mixed with one or more additional mesogen compounds and with or without one or more additives.